Phonograph apparatus



Feb. 3, 1942. H. J. HASBROUCK, JR., ETAL 2,271,976

PHONOGRAPH APPARATUS Filed March 50, 1940 grooving needle of an advance Patented Feb. 3,1942

' UNITED STATE senate rnouocmn mm'rns Harold J. 'Hasbrouck, Jr'.,-Mercha'ntville, N. 1., and Sten E. Bartelson, Indianapolis, Ind assigners to jltadio Corporation of America, a corporation of Delaware Application March 30,1940; Serial No. 826,89'i.

3Claims.

This invention-relates to phonographic apparatus, and-more particularly to recording apparatus used in recording upon blank discs or cylinders which may be played back immediately after recording, the present invention being an improvement upon the copendingapplication of Edward C. Conrad,

Serial No. 253,920, filedJanuary 31, 1939, and 815 signed to Radio Corporation of America.

' In the said copending application, there is disclosed a recording machine wherein the recording head is carried on a cradle and is fed across the record by a feed screw driven from the turntablespindle. In this type of machine, an advance ball": or pre is not always employed, the cutting needle itself forming the groove as it cuts the sound groove in the record blank. With such an arrangement, it has been found that the recording head'partakes of slight vertical oscillations or resonant flutter quency of the dynamic compliance of also be caused to oscillate slightly a vertical direction in response to irregularities in the surface of the blank being cut. or because of vibration induced, for'exampleby building rumble, or the like; This is especially troublesome when recording on lacquer coated discs where the use ball is not practical. As a distortion results when The primary object of vide an improved recorder will be free from More specifically, it is an object of our invention .to provide an improved recorder he mounting which will not oscillate in the manner noted above.

iiis'also an object of our present invention to provide improved means for preventing oscillation of the recorder head which can easily be attached to existing recorders.

In a preferred embodiment of our invention, we secure one end of a short arm to the recording head supporting cradle in a mannersuch that our invention is to prohead mounting which fixedly mounted within the cylinder and extends the aforementioned difficulties.

that disclosed and claimed in ton is smaller than the internaldiameter of the cylinder so that a space is left between the piston and the cylinder walls. in the heavy mass or'piston has a diameter which is slightly'g'reater than the diameter of the guide rod. The massive; piston normally rests on a weak coil spring which is of a strength lust pivotally mounted mersed in oil. when,

at the resonant frethe record sufficient .to overcome the piston, and the casing with oil or other, suitable viscous fill. the space between the guide rod'and the bore in the piston'on the one hand tween the piston and the walls of casing on the other hand. v

It will be seen, from the foregoing brief description, that the heavy piston is entirely imthe effect of gravity on is substantially filled the cylindrical cording head tends to oscillate in a vertical direction, it will carrywith it' the cylindrical casing, but the massive piston will tend. to stand still by reason of its inertia. This or the like to circulate from one end of the cylinder to the other around the mass or piston to result, the record is reproduced.

provide viscous friction. and thus damp the oscillation Since thepistonto overcome the effect of gravity, it does not have-any damping effect. v I Y The novel features that we consider characteristic of our invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, as well as additional 'obiects and advantages thereof, will best be understood from the following embodiment thereof when read in connection. with the accompanying v Figure 1 is a front elevation of a recorder embodying one form f Figure 2 is a sectional view taken on the line description of one drawing in which of our invention,

11-41 of Figure 1, and

Figure 3 is a central proved stabilizer taken on the line nI-m of I Fig. 1.

axially therein from end to end, a relatively pis n.

movement thereon or the pisbeing mount- Referring more particularly to the drawing wherein similar reference characters designate corresponding parts throughout, thereis shown a frame I which rotatably carries a feed screw 3 on which a carriage i is slidably and'rotatably pair of downwardly extending arms to which terminate in apair of aligned bearing members to on which is rotatably mounted a bearing 1. Eccentrically mounted onthe bearing member 1 are a pair of conically tipped screws 9 which pivotally carry a cradle II in a manner more fully Also, the axial bore and the space be 7,

during" operation, the 'recauses the oil;

the coil spring merely supports I sectional view of our immounted. JI'he carriage 5 is provided with a I ally to one side thereof eter slightly greater than that of the cylinder- 35 from moving described in the above noted copending application of Edward C. Conrad. The cradle il comprises a substantially U-shaped member having parallel side arms Ha and a cross arm llb, to the latter of which is secured a sound translating device l3, such as a recording head provided with a needle. or cutter l for cooperation with a record R on a turntable l1.

Pivotally mounted on the carriage 5 is a feed lever i9 which, at its lower end, is provided with a half nut l3a adapted to engage the feed screw 3 to provide driving engagement therebetween so that the assembly or unit comprising the recorder head I3, its cradle I I, the carriage 5 and the lever l9 may be fed across the record R by the feed screw 3.

Secured to the cradle H and extending lateris an arm 2| formed at its outer end witha collar 23 which carries a hollow cylindrical casing 25,-a cover 21 being force fit into the upper end of the casing 25 so as to seal the interior thereof from the atmosphere. A disc 29 which snugly fits within the cylinder 25 rests on the bottom thereof and is provided with a collar or hub 3| from which extends a guide rod 33. The upper end oftheguide rod 33 is received in the bore of a hub 21a on the cover 21, so that the guide, rod 33 is fixed within the casing 25 and extends substantially centrally thereof along its axis.

Slidably mounted in the casing 25 for longitudinal or vertical movement therein is a heavy mass or piston 35 which may be formed of lead or any other heavy metal. The piston .35 is formed with a seat 31 in the bottom thereof; the upper end of a relatively weak coil spring 33 which rests on the disc 29 and surrounds the hub 3| being received within the seat 31. Thus. the piston 35 normally rests on the spring 39, the strength'of the spring 39 being just sumcient to overcome the effect of gravity on the massive piston35.

Thediameter of the piston 35 is appreciably smaller than the internal diameter 0! the casing 25 and it is considerably shorter than the casing 25 so that a space is provided all around Elsie piston between it and the cylinder or casing drawing for the sake of clearness. 1he piston 35 is also provided with a central bore ll through which the rod 33 extends and which has a diamthe rod 33. The cylindrical casing 25 is filled with oil or other suitable viscous medium 43 which fills all the space between the cylinder 25 and the piston 35 in every direction, as well as that, portion oi! the bore ll not occupied by the guide rod 33. It is obvious, from the foregoing description, that the piston 35 .cannot rub against the walls of 25 and that it will slide easily along the guide rod 33, the latter preventing the piston up against the walls of the cylindrical casing 25.

In the operation or our improved vibration This space has been exaggerated in the damper, when the recording head l3 tends to oscillate, it will move the casing 25 with it. However, the massive piston 35 will tend to remain still by reason or its great inertia, and the oil 43 will pass around the piston 35 from one end 01 the casing 25 to the other, thus providing viscous friction, ormechanical resistance, for damping the oscillations of the recorder head. Our improved damping or stabilizing device need not be, tuned to any particular frequency when the casing 25 is filled with oil, and it is eflective over a wide range.

Although we have shown and described but one form of our invention. it will be obvious to those skilled in the art that many other modifications, as well as changes in that described, are possible. We, therefore, do not wish to be limited except insofar as is made necessary by the prior art and by the spirit of the appended claims.

We claim as our invention:

1. A vibration stabilizer tor a phonographic sound translating head which comprises a hollow casing sealed from the atmosphere, a guide rod extending substantially axially'therethrough, a mass having an axial bore extending therethrough of a diameter greater than that of said guide rod, said guide rod extending through-said bore whereby said mass isslidable on said guide rod, said mass also being shorter than and having a smaller cross sectional dimension than said casing whereby it is spaced from said casing in all directions, a relatively weak spring on the the eflect of gravity on said mass.

3. In phonographic apparatus which includes a translating device normally subject to slight mechanical vibrations when cooperating with a record, a. vibration inhibitor for said device which comprises a supporting arm adapted to have connection with said device. a hollow casing carried by said arm and sealed from the atmosphere, a spring on the bottom of said casing, a mass within said casing normally resting on said spring, said mass having an axial bore therein, a guide rod of smaller diameter than said bore extending through said bore and in spaced relation thereto, said .mass being of smaller dimension than said casing in all directions whereby said mass is spaced from said casing in all directions and is freely slidable on said rod between the within said bore not occupied by said guide rod.

HAROLD J. HAsBaoUcx, JR. s'mN 13.3ARTEl-SON. 

